Word lines in dynamic random access memory (DRAM) are commonly heavily loaded. For example, in some DRAM architecture, a word line is coupled to about one thousand (1K) to four thousand (4K) memory cells. In nano-scale technologies, a width of the word lines is narrow. A resistance of the word lines is high, which causes a large propagation delay along the word lines, and affects performance of the DRAM. To solve the problem, repeaters to recover integrity of signals on the word lines may be asserted along the word lines; two-metal layers mechanisms may be used for the word lines, etc. In such solutions, disadvantages, such as inefficiency, a larger die area, additional layers, etc., however, outweigh advantages.
Commonly known, a first transistor is called stronger than a second transistor when the driving capability of the first transistor is larger than that of the second transistor. Explained in a different way, an operational current of the first transistor is higher than that of the second transistor when the voltages applied to ports of the two transistors are the same.
Like reference symbols in the various drawings indicate like elements.